1. Technical Field
The invention relates to a semiconductor device that transmits and receives a signal using an inductor, an electronic apparatus, and a method of manufacturing a semiconductor device.
2. Related Art
In the case where an electric signal is transferred between two circuits having different electric potentials of input electric signals, a photocoupler is frequently used. The photocoupler has a light emitting element such as a light emitting diode and a light receiving element such as a phototransistor, and transfers an electric signal by converting the input electric signal into light in the light emitting element and returning the light to the electric signal in the light receiving element. However, since the photocoupler has the light emitting element and the light receiving element, miniaturization thereof is difficult. Further, in the case where the electric signal has a high frequency, the photocoupler is unable to follow the electric signal. As a technique for solving this problem, a technique of transferring an electric signal by arranging two (one set of) inductors to face each other and inductively coupling the respective inductors to each other has been developed.
In Japanese Laid-open patent publication NO. 2006-066769 and Japanese Laid-open patent publication NO. 2005-005685, two (one set of) inductors, that is, vertical (FIG. 1) and horizontal (FIG. 2) inductors, are arranged to face each other in one semiconductor chip using a multilayer interconnect of the semiconductor chip. They may be manufactured in a standard CMOS process, and the positional precision of the two inductors arranged to face each other can be heightened.
Further, a semiconductor device described in Japanese Laid-open patent publication NO. 2007-123650 and Japanese Laid-open patent publication NO. 2007-123649 has a first inductor and a second inductor. In this semiconductor device, input and output signal terminals are isolated from each other. The first inductor is installed in a first semiconductor chip, and generates an electromagnetic signal based on the electric signal input to an input unit. Further, the second semiconductor inductor is installed in a second semiconductor chip, generates an electric signal through reception of the electromagnetic signal from the first inductor, and outputs the generated electric signal through an output unit. The first semiconductor chip and the second semiconductor chip are installed on respective lead frames, and are arranged to face each other in a state where the first and second inductors are electrically isolated from each other. Accordingly, the first inductor and the second inductor are not in electrical contact with each other, and thus it becomes possible to easily achieve isolation between the first inductor and the second inductor. Further, since no thick isolation layer is installed between the inductors, it is possible to manufacture the semiconductor device in a standard CMOS process.